Apparatuses and methods consistent with exemplary embodiments of the inventive concept relate to a pixel for an image sensor such as a complementary metal-oxide-semiconductor (CMOS) image sensor and an image sensor including the same.
CMOS image sensors are solid-state sensing devices using CMOS. CMOS image sensors have lower manufacturing costs and a smaller size than charge coupled device (CCD) image sensors having a high-voltage analog circuit. Thus, CMOS image sensors have an advantage of low power consumption. In addition, the performance of CMOS image sensors has been improved as compared to an early development stage, and therefore, CMOS image sensors are usually used for various electronic appliances including portable devices such as smart phones and digital cameras.
A pixel array included in a CMOS image sensor includes a photoelectric conversion element in each pixel. The photoelectric conversion element generates an electrical signal varying with the quantity of incident light. The CMOS image sensor processes electrical signals to synthesize an image. With the recent requirement of high-resolution images, pixels included in the CMOS image sensor are required to be much smaller.
With the requirement of miniaturization, the size of pixels for image sensors gets smaller. With the decrease of the size of pixels, the area of an isolation film (e.g., a deep trench isolation (DTI)) formed between pixels has become an issue. The DTI is a dead zone that does not receive light. The quantity of light received by each pixel in a pixel array with DTI is less than that in a pixel array without DTI.